This invention relates to a load break switch assembly and more particularly to a load break switch and enclosure wherein the switch handle acts as an interlock for the enclosure door.
As its name implies, a load break switch functions to open a circuit when current is flowing. There are many uses for load break switches for controlling various types of electrical equipment. In some environments, it is desirable to enclose the load break switch in an enclosure or cabinet to prevent access by unauthorized persons as well as protect components from the atmosphere. It is easily seen that merely placing a load break switch in a cabinet will not prevent access by unauthorized persons. It is possible to use a padlock or other type of lock to securely lock the cabinet door to limit access only to those persons having the combination or a key. While this method works, it is not practical because people must remember the combination or many keys have to be made. It will be appreciated that it would be highly desirable to have an enclosure for a load break switch which limits access without using cumbersome locks and keys.
In some types of electrical apparatus, it is common to use interlock mechanisms which cooperate with the door to the enclosure so that the door cannot be opened when the circuit is closed. This is a practical solution; however, some interlock mechanisms can be expensive to manufacture and fairly complicated. It is desirable to have a simple mechanism which is easy to manufacture and use.
Another problem with placing load break switch mechanisms inside cabinets is that the interior of the cabinets tend to be cluttered and rather unsightly. The interior of the cabinet will contain bus bars for carrying current to and from the load as well as numerous insulators and spacers to insulate the bus bar from the metal components of the cabinet. Similarly, the components of the load break switch are usually bulky and cumbersome and require numerous insulators to insulate them from the metal components of the cabinet. Typically, the load break switches are three-phase or three-pole mechanisms which have a longitudinal axis which is oriented horizontally in the cabinet. With the switch assembly oriented in this fashion, the bus bars are conveniently run along the back wall of the cabinet. One difficulty with this arrangement is that with this horizontal orientation of the switch assembly, the operating handle protrudes from the left or right sidewall of the cabinet. This limits what can be placed next to a particular load break switch cabinet. Accordingly, it can be appreciated that it would be highly desirable to provide a load break switch assembly which does not have a handle protruding from the sidewalls of the enclosure.
As mentioned above, typical interlock mechanisms are constructed so that they work in conjunction with the operating handle or the door. One type of load break switch which has the interlock mechanism associated with the handle uses a complicated chain drive which reacts to movement of the handle to open the load break switch in response to the handle movement. Because this mechanism contains chains and numerous parts, it is expensive to manufacture, bulky and requires a certain amount of space in the enclosure. It can be appreciated, that it would be highly desirable to provide a simple interlock mechanism which uses a minimal amount of space on the interior of the cabinet and does not require the use of chains.
Accordingly, it is an object of the present invention to provide a load break switch assembly which can be mounted in an enclosure.
Another object of the present invention is to provide a load break switch assembly which is mounted in an enclosure which can be placed side-by-side with other enclosures.
Another object of the invention is to provide a load break switch and enclosure which uses the operating handle as an interlock.